Technical Field
The present disclosure relates to a radiation-hard electronic device and to a method for protecting an electronic device from ionizing radiation.
Description of the Related Art
As is known, electronic devices may generally undergo damage of a various nature and seriousness from exposure to ionizing radiation. Damage may derive both from the total dose of radiation absorbed and from single events, and may range from a disturbance of a minor degree to a catastrophic breakdown, which causes destruction of the devices.
Damage deriving from the total dose of radiation absorbed presents progressively and usually may be put down to phenomena of trapping of the charge generated by interaction with the incident radiation. A typical effect is drift of the threshold voltages of MOS transistors as a result of the charge trapped in the gate insulating regions.
Single events are instead due to impact of high-energy particles on the semiconductor substrates in which the devices are formed. Interaction with the substrate gives rise to an intense generation of charge carriers along the paths of the high-energy particles. In turn, the charge carriers are at the origin of drift and diffusion currents that may cause phenomena equivalent to electrostatic discharge, such as triggering of parasitic components or the phenomena of junction breakdown. In some conditions, the phenomena may have intensities such as to cause permanent damage to, or even destruction of, the devices.
Devices designed for operating in environments exposed to ionizing radiation should evidently be provided with protection structures or arrangements that enable mitigation of the adverse effects both of accumulation of radiation doses over time and of single events. Operating conditions that require adoption of measures against damage from ionizing radiation are encountered regularly in space applications (e.g., satellites, spacecraft, space stations) or else in nuclear sites.
The structural, circuit, and process solutions adopted for preserving devices from radiation offer a certain degree of protection, but not always are sufficiently robust to prevent malfunctioning and breakdown, especially in critical applications.
It would thus be desirable to have available more effective protection systems for reducing the risk of temporary and/or permanent damage of electronic devices.